Touch fasteners their manufacture and products incorporating them

ABSTRACT

A composite touch fastener has an elongated, sheet-form resin substrate, a fibrous loop strip partially encapsulated in, or otherwise permanently attached to, resin of the substrate, and an array of loop-engageable fastener elements integrally molded with resin of the substrate. The loop strip forms a discrete band of hook-engageable, free-standing loops along the length of the substrate, and has a substantially constant fiber density across its width. The array of fastener elements is arranged in a discrete band of fastener elements extending longitudinally along the substrate. The fastener product is useful as a repeated use bag closure, with a pair of grooves and a graspable rib integrally molded into the substrate between the fastener elements and loops. The center portion of the closure seals the bag until it is torn away to expose the mating bands of loops and fastener elements. Methods and apparatus are disclosed for continuously molding the resin of the substrate while permanently attaching preformed material, such as loop material staked in discrete regions, to resin of the substrate.

BACKGROUND OF THE INVENTION

This invention relates generally to touch fasteners, and specifically tocomposite touch fasteners having both loops and loop-engageable fastenerelements extending from one side of a common substrate, to theirapplication in products such as closure strips for reclosable bags, andto methods and apparatus for their manufacture.

There has been much development over the last thirty years in the fieldof hook-and-loop fasteners. Early touch fastener products of this typeconsisted of two mating tapes, each being knit or woven. One tape wouldinclude loops of filament woven into a base, and the other would includefilaments woven to form loops and then cut to form hooks. In some casesfree ends of drawn plastic filaments on the male tape would be melted toform protruding heads. This shape of fastener element is sometimescalled a “mushroom”, to distinguish it from “hook”-shaped elements withre-entrant crooks.

More recently, continuous molding of fastener elements extending from acommon sheet-form resin base has resulted in less expensive and thinnermale tapes. Significant improvements in this area include thedevelopment of continuous fastener tape molding using fixed moldcavities (see Fischer, U.S. Pat. No. 4,794,028), and the ability toprovide loops on the back side of the male fastener tape as the fastenertape substrate and elements are being formed (see Kennedy et al., U.S.Pat. No. 5,260,015), thus creating a composite fastener tape capable offastening to itself. Further improvements have reduced the size of thefastener elements moldable by such techniques, to heights of 0.015 inchor less, which provide a very smooth touch when arranged in densearrays.

As molded fastener tape has been improved to be more flexible and lessexpensive, it has found application in disposable garments, such asdiapers. Further improvements are desirable to extend the applicabilityof molded touch fastener products to other uses.

One such use that is discussed in more detail below is as a closure forreclosable bags and other such packaging. Other types of repeated useclosures for such bags include, for instance, the rib-and-groove type ofclosure such as is marketed under the name ZIPLOCK.

SUMMARY OF THE INVENTION

The invention features, in several of its aspects, a composite touchfastener product having both a band of loops and a band of hooksextending from a single face of a common, sheet-form substrate. Amongother applications, this product can be included at the opening of a bagto function as a repeated use closure.

According to one aspect of the invention, an elongated closure stripincludes a sheet-form resin substrate having a front face, a loop stripcarried on the front face of the substrate, and an array ofloop-engageable fastener elements integrally molded with resin of thefront face of the substrate. The loop strip comprises a non-woven web offibers forming a discrete band of hook-engageable loops extending alongthe length of the closure strip, and the array of fastener elementsforms a discrete band of fastener elements extending longitudinallyalong the length of the closure strip and spaced apart from the band ofloops.

The closure strip is preferably constructed to be folded along a regionbetween the bands of fastener elements and loops to place these bands inreleasable engagement.

In some embodiments, the loop strip comprises a non-woven web ofentangled fibers forming the loops and having a basis weight of lessthan about 4 ounces per square yard (preferably, less than about 2ounces per square yard). In some cases, the non-woven web comprises aneedled web in a stretched condition.

In some embodiments, fibers of the loop strip are affixed to thesubstrate across the width of the loop strip, such as by beingencapsulated by resin of the substrate.

By “width” of the loop strip, we mean the entire transverse dimension ofthe preformed strip, as measured between the outermost edges of thepreformed strip before it is attached to the substrate.

In many cases, the loop strip has a fiber density which is substantiallyconstant across its width, yet the loop strip has discrete regions whichare more encapsulated by resin than other regions of the loop strip.These discrete, more encapsulated regions may be spaced apartlongitudinally along the loop strip, extend lengthwise along the loopstrip and be spaced apart widthwise, or be arranged in a checkerboardpattern, for instance.

When we refer to regions of the loop strip as being more “encapsulated”than other regions, we mean that the fibers of the more encapsulatedregions are generally more thoroughly embedded in the resin of thesubstrate than the fibers of other regions. Generally, this will involvea deeper penetration of the substrate resin into the loop strip.

In some embodiments, longitudinal edge regions of the loop strip areaffixed to the substrate, while a center region (between the edgeregions) is substantially loose from the substrate. The center region ofthe loop strip may advantageously define a gentle arc extending awayfrom the substrate in some of these embodiments.

In some configurations, a barrier layer (of a different material thanthe substrate) is included between the substrate and the loop strip.This barrier layer may be of paper or a polymer resin, for example.

In some cases the loop strip has at least one edge which issubstantially loose from the substrate. This edge may be either an inneror outer edge in a finished bag, and can help to redirect peelseparation forces to enhance the peel strength of the fastening.

In some closure strips, open-ended pockets are defined between an edgeof the loop strip and the substrate. These pockets can also help toenhance peel strength in some cases.

In some embodiments, the edge regions of the loop strip have fibersdirectly encapsulated within resin of the substrate, while the closurestrip also includes a binder (of a different material than thesubstrate) connecting fibers of the center region (between the edgeregions) of the loop strip to resin of the substrate.

In some presently preferred embodiments, the substrate defines a pair ofgrooves extending longitudinally along the length of the closure stripbetween the band of loops and the band of fastener elements. Thesegrooves are preferably lengthwise continuous and defined by moldedsurfaces in the front face of the substrate.

The closure strip also includes, in some cases, a longitudinal ribintegrally molded with and extending from the front face of thesubstrate between the band of loops and the band of fastener elements.In some of these cases, the rib is disposed between the pair of groovesjust described.

In some embodiments, the front face of the substrate has twolongitudinal edge regions void of fastener elements and loops, forpermanently adhering the substrate to the sides of a bag. These edgeregions may be covered with a layer of adhesive for permanentlyattaching the closure strip to opposite sides of a bag, or compriseexposed resin of the substrate, for permanently welding the closurestrip to opposite sides of a bag formed of a compatible material. Theselongitudinal edge regions may alternatively be disposed on the back faceof the substrate.

The substrate of some embodiments of the closure strip is advantageouslyformed of polyethylene, such as for welding the substrate topolyethylene bag material.

Some embodiments of the closure strip also include an adhesive stripcarried on the front face of the substrate between the band of fastenerelements and the band of loops. The adhesive strip has an exposedsurface arranged to contact the front face of the closure strip when theclosure strip is folded to engage the loops with the fastener elements,to retain the closure strip in a folded state.

Alternatively, some embodiments have a first adhesive strip carried onthe front face of the substrate between the band of fastener elementsand the pair of grooves, and a second adhesive strip carried on thefront face of the substrate between the band of loops and the pair ofgrooves. The first and second adhesive strips have exposed surfacesarranged to contact each other when the closure strip is folded toengage the loops with the fastener elements, to retain the closure stripin a folded state. In either case, these adhesive strips canadvantageously provide an air-tight seal when the closure is closed.

In some embodiments, the closure strip includes a layer of paperpermanently adhered to the substrate. In some cases, this layer of paperis carried on the front face of the substrate, in its longitudinal edgeregions. In some cases, the paper is carried on the back face of thesubstrate. In some other cases, the layer of paper is disposed between acenter region of the loop strip and the substrate.

According to a second aspect of the invention, an elongated closurestrip includes a sheet-form resin substrate having front and back faces,a loop strip carried on the front face of the substrate, and an array ofloop-engageable fastener elements carried on the front face of thesubstrate. The loop strip forms a discrete band of hook-engageable,free-standing loops along the length of the closure strip, and the arrayof fastener elements forms a discrete band of fastener elementsextending longitudinally along the length of the closure strip andspaced apart from the band of loops. The substrate defines a pair ofgrooves extending longitudinally along the length of the closure stripbetween the band of loops and the band of fastener elements, and alongitudinal rib integrally molded with and extending from the substratebetween the pair of grooves.

In some embodiments, the loop strip comprises a non-woven web ofentangled fibers forming the loops and having a basis weight of lessthan about 4 ounces per square yard (preferably, less than about 2ounces per square yard).

In some cases, the grooves and rib are disposed on the front face of thesubstrate. In other cases, they are disposed on its back face.

Various embodiments of this aspect of the invention contain variousfeatures described above with respect to the first aspect of theinvention.

According to a third aspect of the invention, an elongated closure stripincludes a sheet-form resin substrate having front and back faces, aloop strip carried on the front face of the substrate, and an array ofloop-engageable fastener elements carried on the front face of thesubstrate. The loop strip forms a discrete band of hook-engageable,free-standing loops along the length of the closure strip, and the arrayof fastener elements forms a discrete band of fastener elementsextending longitudinally along the length of the closure strip andspaced apart from the band of loops. The loop strip has width and afiber density which is substantially constant across its width, and isat least partially encapsulated in resin of the substrate across itswidth, with the loop strip having discrete regions which are moreencapsulated by resin than other regions of the loop strip.

Preferably, the fastener elements are integrally molded with resin ofthe substrate.

Various embodiments of this aspect of the invention contain variousfeatures described above with respect to the first aspect of theinvention.

According to a fourth aspect of the invention, a reclosable bag includesa bag body and an elongated closure strip. The bag body has two opposingside walls joined along three edges to form therebetween a pouch havingan open end. The closure strip is permanently affixed to the two sidewalls of the bag body along the open end, and includes a sheet-formresin substrate having a front face, a loop strip carried on the frontface of the substrate, and an array of loop-engageable fastener elementsintegrally molded with resin of the front face of the substrate. Theloop strip forms a discrete band of hook-engageable, free-standing loopsalong the length of the closure strip, and the array of fastenerelements forms a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and arranged toengage the band of loops to releasably retain the bag in a closedcondition when the opposing sides of the bag body are pressed togetherat the open end.

Preferably, the loop strip of the closure strip comprises a non-wovenweb of entangled fibers forming the loops and having a basis weight ofless than about 4 ounces per square yard (more preferably, less thanabout 2 ounces per square yard).

In some embodiments, the substrate of the closure strip defines a pairof grooves extending longitudinally along the length of the closurestrip between the band of loops and the band of fastener elements, thepair of grooves spaced apart to define between them a band of substrateresin for retaining the bag in a closed condition until the closurestrip is torn along the pair of grooves.

For some applications, the substrate is continuous and solid between theband of loops and the band of hooks and forms a seal to retain the bagin a sealed condition until the closure strip is torn along the pair ofgrooves.

In some embodiments, the substrate of the closure strip is permanentlyaffixed to the side walls of the bag body with adhesive. In some otherembodiments, the substrate of the closure strip is welded to the sidewalls of the bag body. The substrate of the closure strip and the sidewalls of the bag body may both be formed of polyethylene, for instance.

The closure strips of various embodiments of this aspect of theinvention contain various features described above with respect to thefirst aspect of the invention.

According to a fifth aspect of the invention, a reclosable bag includesa bag body having two opposing side walls joined along three edges toform a pouch having an open end, and a closure strip permanently affixedto the two side walls of the bag body along the open end. The closurestrip includes a sheet-form resin substrate having a front face, a loopstrip carried on the front face of the substrate, and an array ofloop-engageable fastener elements carried on the front face of thesubstrate. The loop strip forms a discrete band of hook-engageable,free-standing loops along the length of the closure strip, and the arrayof loop-engageable fastener elements forms a discrete band of fastenerelements extending longitudinally along the length of the closure stripand arranged to engage the band of loops to releasably retain the bag ina closed condition when the opposing sides of the bag body are pressedtogether at the open end. The substrate defines a pair of groovesextending longitudinally along the length of the closure strip betweenthe band of loops and the band of fastener elements, the pair of groovesspaced apart to define between them a band of substrate resin forretaining the bag in a closed condition until the closure strip is tornalong the pair of grooves. The substrate also defines a longitudinal ribintegrally molded with and extending from the substrate between the pairof grooves, the rib having thickness and arranged to be grasped betweenadjacent regions of the substrate and pulled to tear the closure stripalong the pair of grooves.

In some embodiments, the substrate is continuous and solid between theband of loops and the band of hooks and forms a seal to retain the bagin a sealed condition until the closure strip is torn along the pair ofgrooves.

Preferably, the fastener elements are integrally molded with resin ofthe substrate.

According to a sixth aspect of the invention, a method of fabricating aclosure strip is provided. The closure strip is in the form of asheet-form resin substrate having a front face, with both a loop stripand an array of loop-engageable fastener elements carried on the frontface of the substrate. The loop strip has width and forms a discreteband of hook-engageable, extended loops along the length of the closurestrip. The array of loop-engageable fastener elements forms a discreteband of fastener elements extending longitudinally along the length ofthe closure strip and spaced apart from the band of loops, the substratehaving a frangible section between the band of loops and the band offastener elements. The method includes the steps of molding acontinuous, sheet-form substrate having both a band of fastener elementsintegrally molded with and extending from its front face, and afrangible section, and attaching a continuous strip of loop material toresin forming the front face of the substrate to form a band of loops,with the frangible section of the substrate disposed between the band ofloops and the band of fastener elements.

In some embodiments, the frangible section defines a pair oflongitudinally extending grooves in the substrate, and the step ofmolding includes forming the grooves in the substrate as the substrateis formed. The step of molding also includes, in some instances,simultaneously forming a longitudinal rib extending from the substratebetween the pair of grooves. In some cases, the rib and grooves aremolded on the front face of the substrate.

In some embodiments, the step of attaching encapsulates fibers of thestrip of loop material in resin of the substrate across the width of thestrip of loop material.

In some embodiments where the strip of loop material has a fiber densitywhich is substantially constant across its width, the step of attachingincludes permanently bonding discrete regions of the strip of loopmaterial to the substrate while leaving other regions of the strip ofloop material in a less bonded condition.

In some embodiments of the method, the strip of loop material ispermanently attached to the substrate after the substrate is molded. Forinstance, the strip of loop material may be attached to the substrate byheating the front face of the substrate and then pressing the loopmaterial against the front face of the substrate with the front face ofthe substrate at an elevated temperature.

In some other embodiments, the strip of loop material is permanentlyattached to the substrate as the substrate is molded. For instance, inone preferred method the steps of molding and attaching includecontinuously feeding the strip of loop material through a nip definedbetween a rotating mold roll and a pressure roll (the rotating mold rolldefining a multiplicity of cavities about its periphery for molding thefastener elements) while continuously introducing molten resin to themold roll under conditions which cause the resin to fill the cavitiesand form the substrate, such that pressure in the nip bonds the strip ofloop material to resin of the substrate.

In some cases, the mold roll has two extending ridges that form a pairof grooves in the substrate.

The step of molding, in some embodiments, includes simultaneouslyforming a longitudinal rib extending from the substrate between the pairof grooves (the mold roll defining, between its two ridges, a channelfor forming the longitudinal rib).

In some other embodiments in which the strip of loop material ispermanently attached to the substrate as the substrate is molded, thesteps of molding and attaching include continuously feeding the strip ofloop material through a gap defined between a rotating mold roll and astationary extrusion head (the rotating mold roll defining amultiplicity of cavities about its periphery for molding the fastenerelements), while continuously introducing molten resin to the gap underconditions which cause the resin to fill the cavities and form thesubstrate and to permanently adhere to the strip of loop material.

For some applications the method also includes, while continuouslyfeeding the strip of loop material through the gap, continuously feedinga strip of preformed material through the gap between the strip of loopmaterial and the extrusion head, such that the preformed materialinhibits the encapsulation of fibers of the strip of loop material inpredetermined regions and the preformed material is incorporated intothe closure strip.

This preformed material is preferably selected from the group consistingof paper, fabric and plastic film, and may have perforations through itfor allowing heavier penetration of substrate resin in somepredetermined areas.

The closure strips employed in various embodiments of this aspect of theinvention contain various features described above with respect to thefirst aspect of the invention.

According to a seventh aspect of the invention, a method of fabricatingreclosable bags is provided. The method includes the steps of:

(a) providing a continuous length of sheet-form plastic, folded alongits length and having two exposed longitudinal edges;

(b) providing a continuous closure strip folded along its length andhaving two exposed longitudinal edges (the closure strip having asheet-form resin substrate with a front face, a loop strip carried onthe front face of the substrate and forming a discrete band ofhook-engageable, free-standing loops along the length of the closurestrip, and an array of loop-engageable fastener elements integrallymolded with the front face of the substrate and forming a discrete bandof fastener elements extending longitudinally along the length of theclosure strip and spaced apart from the band of loops, as describedabove);

(c) permanently attaching the longitudinal edges of the sheet-formplastic to the longitudinal edges of the closure strip to form acontinuous preform tube; and

(d) forming sealed individual bags from the preform tube.

In some embodiments, the step of forming sealed individual bags includescutting the continuous preform tube to predetermined lengths (each cutlength comprising a section of closure strip and a section of sheet-formplastic), sealing a first open end of each cut length of preform tube,and sealing a second open end of each cut length of preform tube to forma sealed bag. In many cases, between the steps of sealing the first andsecond open ends, each cut length of preform tube is filled withmaterial to be stored in the sealed bag.

In some embodiments, the step of forming sealed individual bagsincludes:

(d1) sealing the tube at a sealing point spaced from one end of the tubeto form an end pouch with a single opening;

(d2) filling the end pouch with material;

(d3) sealing the single opening of the end pouch to form a sealed bagcontaining the material;

(d4) separating the sealed bag from the tube by severing the tube belowthe sealing point;

(d5) advancing the tube; and

(d6) repeating steps (d1) through (d5).

In some embodiments, the substrate of the closure strip defines a pairof grooves extending longitudinally along the length of the closurestrip between the band of loops and the band of fastener elements, withthe pair of grooves spaced apart to define between them a band ofsubstrate resin for retaining the bag in a closed condition until theclosure strip is torn along the pair of grooves.

The closure strips employed in various embodiments of this aspect of theinvention contain various other features described above with respect tothe first aspect of the invention.

According to an eighth aspect of the invention, a composite touchfastener has an elongated, sheet-form resin substrate with a front face,a fibrous loop strip partially encapsulated in resin of the front faceof the substrate, and an array of loop-engageable fastener elementsintegrally molded with resin of the front face of the substrate. Theloop strip forms a discrete band of hook-engageable, free-standing loopsalong the length of the substrate, the loop strip having a substantiallyconstant fiber density across its width between its two longitudinaledges. The array of loop-engageable fastener elements forms a discreteband of fastener elements extending longitudinally along the substrate.

In some embodiments, the loop strip comprises a non-woven web ofentangled fibers forming the loops. Preferably, the web has a basisweight of less than about 4 ounces per square yard (more preferably,less than about 2 ounces per square yard). The non-woven web may be inthe form of a needled web in a stretched condition, for instance.

Various composite touch fasteners of this aspect of the inventioncontain features described above with respect to the first aspect of theinvention.

According to a ninth aspect of the invention, a composite touch fastenerincludes an elongated, sheet-form resin substrate, a fibrous loop strippartially encapsulated in resin of the substrate, with the loop striphaving discrete regions which are substantially more encapsulated byresin than other regions thereof, and an array of loop-engageablefastener elements integrally molded with resin of the substrate.

In some embodiments, the loop strip has a substantially constant fiberdensity across its width.

In some cases, the strip of loop material has regions of substantiallyhigher loft than regions corresponding to the discrete regions which aresubstantially more encapsulated by resin.

By “loft”, we mean the distance the exposed loops of the loop materialextend from the front face of the substrate, as presented for engagementby fastener elements.

In some embodiments, the strip of loop material comprises a non-wovenweb of entangled fibers forming the loops and having a basis weight ofless than about 4 ounces per square yard.

Various composite touch fasteners of this aspect of the inventioncontain features described above with respect to the first aspect of theinvention.

According to a tenth aspect of the invention, a method of fabricating acomposite touch fastener is provided. The composite touch fastener is inthe form of an elongated, sheet-form resin substrate having a frontface, with both a loop strip and an array of loop-engageable fastenerelements carried on the front face of the substrate. The loop strip haswidth and forms a discrete band of hook-engageable, exposed loopsextending longitudinally along the substrate. The array ofloop-engageable fastener elements forms a discrete band of fastenerelements extending longitudinally along the length of the substrate. Themethod includes the steps of molding a continuous, sheet-form substratehaving a band of fastener elements integrally molded with and extendingfrom its front face, and attaching a continuous strip of loop materialto resin forming the front face of the substrate to form a band ofloops.

Preferably, the strip of loop material comprises a non-woven web ofentangled fibers forming the loops and having a basis weight of lessthan about 4 ounces per square yard (more preferably, less than about 2ounces per square yard).

In some embodiments, the strip of loop material has a fiber densitywhich is substantially constant across its width, yet the step ofattaching permanently bonds discrete regions of the strip of loopmaterial to the substrate while leaving other regions of the strip ofloop material in a less bonded condition.

In some cases, the strip of loop material is permanently attached to thesubstrate as the substrate is molded. For instance, in some preferredmethods, the steps of molding and attaching include continuously feedingthe strip of loop material through a gap defined adjacent a rotatingmold roll (defining a multiplicity of cavities about its periphery formolding the fastener elements), while continuously introducing moltenresin to the mold roll under conditions which cause the resin to fillthe cavities and form the substrate, such that pressure in the gap bondsthe strip of loop material to resin of the substrate.

In some cases, the gap is a nip defined between the mold roll and apressure roll.

In some other cases, the gap is defined between the mold roll and afixed extrusion head.

In some embodiments, the mold roll contains at least one staking ringhaving a contoured outer edge, the staking ring arranged to hold apredetermined region of the strip of loop material against the resinunder pressure in the gap.

In one presently preferred configuration, the outer edge of the stakingring has protrusions spaced about its periphery, the protrusionscorresponding to discrete regions of relatively greater encapsulation ofthe strip of loop material.

In some cases, the mold roll has multiple staking rings arranged toproduce a predetermined bonding pattern across the strip of loopmaterial.

According to a eleventh aspect of the invention, a method of fabricatinga composite touch fastener is provided. The touch fastener is in theform of an elongated sheet-form resin substrate carrying both apreformed material and an array of loop-engageable fastener elementsintegrally molded with the substrate. The method includes molding acontinuous, sheet-form substrate having a band of fastener elementsintegrally molded with and extending from the substrate, by continuouslyintroducing molten resin to a gap defined adjacent a rotating mold rolldefining a multiplicity of cavities about its periphery for molding thefastener elements, under conditions which cause the resin to fill thecavities and form the substrate, while permanently attaching acontinuous strip of preformed material to resin of the substrate in anip defined between the mold roll and a pressure roll, by causingpressure variations within the nip. The pressure variations result inregions of relatively high penetration of substrate resin into thepreformed material and regions of relatively low penetration ofsubstrate resin into the preformed material.

In some preferred embodiments, the mold roll has protrusions extendingradially into the nip, for causing local increases in nip pressure thatcorrespond to the regions of relatively high penetration of substrateresin.

In some embodiments, the pressure roll has protrusions extendingradially into the nip, the protrusions causing local increases in nippressure that correspond to the regions of relatively high penetrationof substrate resin.

In some cases, the gap and the nip are coextensive. In some other cases,the gap is defined between the mold roll and a fixed extrusion head.

In some embodiments, the regions of relatively high penetration ofsubstrate resin into the preformed material are arranged in acheckerboard pattern along the strip of preformed material.

In some configurations, the array of fastener elements is disposed on afront face of the substrate and the strip of preformed material isattached to a back face of the substrate. The preformed material is, insome embodiments, coextensive with the back face of the substrate.

In some other configurations, the strip of preformed material and thearray of fastener elements are both disposed on a common side of thesubstrate.

In some embodiments, the strip of preformed material comprises a stripof loop material having exposed loops arranged for releasable engagementby the fastener elements.

According to a twelfth aspect of the invention, an apparatus forfabricating a composite touch fastener is provided. The composite touchfastener, as described above, is in the form of an elongated sheet-formresin substrate having a front face, a loop strip carried on the frontface of the substrate (the loop strip having width and forming adiscrete band of hook-engageable, extended loops along the length of thetouch fastener), and an array of loop-engageable fastener elementscarried on the front face of the substrate and forming a discrete bandof fastener elements extending longitudinally along the substrate. Theapparatus includes a rotating mold roll defining a multiplicity of fixedcavities about its periphery for molding the fastener elements, means ofsupplying molten resin to the mold roll under conditions which cause theresin to fill the cavities and form the substrate, means of supplying acontinuous strip of loop material between the molten resin and the moldroll under conditions which cause the strip of loop material topermanently bond to the front face of the substrate, and means ofstripping the fastener elements from the cavities. The “means” elementsof the apparatus will be understood to be those discussed or representedschematically herein or in the disclosures incorporated by reference,and their equivalents.

As a repeated use closure, the product of the invention provides aventilated, easily alignable seal. As the bands of loops and fastenerelements are relatively wide, there is no need for accurate alignment toform a reliable closure. The closure is able to accommodate a fairamount of dirt or debris without losing its function as a closure,making it particularly applicable as a closure for bags containinggranular or powder substances. In addition, the natural porosity of theclosure can provide some degree of filtering of airborne dust. Such aventilated closure can be particularly desirable in cargo containers ofairplanes in order to accommodate pressure changes, and, by its ventingaction, may help to avoid moisture buildup to keep produce and othersuch items fresh. The groove and rib tear strip molded into the centerof the closure strip in some cases advantageously maintains an air-tightseal until the bag is initially opened. The continuous closure stripprovided by the invention is readily adaptable to standard bag-makingequipment and, in many instances, is directly weldable to compatible bagmaterials. These advantages accrue to bags produced according to theinvention and having such a repeated use closure.

If made of an appropriate width, the closure strip of the invention canbe folded and sealed to itself to form an enclosed bag.

By employing a very light, non-woven loop material and integrally moldedfastener elements in several instances, the resulting product isrelatively inexpensive and flexible.

The product of the invention is also useful in other applications,either as a packaging closure or as a general purpose fastener.Encapsulating fibers of the loop material in a predetermined pattern ofalternating regions of light and heavy encapsulation can produce regionsof particularly high loft in which hook-engageable fibers areparticularly well-presented for engagement.

As a method of producing fastener products, the invention also providesa reliable method of securing very lightweight loop materials to thefront face of a resin substrate having fastener elements, in many caseswithout adhesives and while the substrate and fastener elements arethemselves being formed, eliminating a post-forming attachment step. Themethod does not require the loop material to have a variable fiberdensity to provide for variable resin penetration, and can thereforeaccommodate and locally bond loop materials having a homogeneous fiberdensity. As fibers of the loop material are, in many instances, directlyencapsulated within resin of the substrate, undesirable delamination ofloop material from the substrate is avoided during high peel loads. And,as the fastener elements are, in many cases, integrally molded with thesubstrate, delamination between the fastener elements and the substrateis also avoided. The fastener elements and resin substrate (includingany tear strip features such as ribs and grooves appropriate for closurestrips) can be molded in a single continuous process from the same flowof resin, with the loop material fed right through the substrate-forminggap or nip on the side of the resin adjacent the fastenerelement-forming mold roll.

By appropriately controlling the forming speed and resin temperature andpressure (the optimal values of which are interdependent and will dependon the type of resin employed and the geometry of the product, as willbe understood by those of normal skill in the art), the resultingpenetration of substrate resin into the loop material may be controlledso as to not completely flood the exposed surface of loops with resin.In many applications, the use of appropriately contoured staking ringsin the region of the mold roll adjacent the loop material can help toform a pattern of lofted regions of loop material which are lesspenetrated by resin than other areas. Such lofted regions can extendloops for ready engagement by fastener elements.

The apparatus of the invention can provide an efficient means ofcarrying out the steps of the inventive method described above, toproduce a continuous strip of fastener product.

Other features and advantages of the invention will be apparent from thefollowing description of embodiments, and from the claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a composite touch fastener in the formof a closure strip.

FIGS. 1A and 1H are enlarged views of areas 1A and 1H, respectively, inFIG. 1.

FIGS. 1B through 1G illustrate the structure of area 1A in various otherclosure strip embodiments.

FIG. 2A illustrates the application of fill-shifting loads in a baghaving the closure strip of FIGS. 1 and 1B.

FIG. 2B illustrates the application of peel force to the closure stripof FIGS. 1 and 1B.

FIG. 3 is a cross-sectional view of the closure strip, folded andinstalled at the opening of a bag in a sealed condition.

FIGS. 4A and 4B illustrate a bag with the closure strip of FIG. 1, insealed and opened conditions, respectively.

FIG. 5 is an enlarged cross-sectional view of the outer edge of theclosure strip being grasped to open the bag.

FIG. 6 is a perspective view of a closure strip having a paper backing.

FIG. 7 illustrates a first method and apparatus for forming compositetouch fastener tapes, such as the closure strips of FIGS. 1 and 6.

FIG. 8 is an enlarged, unscaled view of the forming nip of the apparatusof FIG. 7.

FIG. 9 is a highly enlarged view of the loop material securing region ofthe nip of FIG. 8.

FIG. 9A illustrates an alternative arrangement of the loop materialstaking region.

FIG. 10 is an enlarged view of a portion of the outer edge of a stakingring.

FIG. 11 illustrates a second method and apparatus for forming compositetouch fastener tapes, such as the closure strips of FIGS. 1 and 6.

FIG. 12 illustrates a method and apparatus for forming bags.

FIG. 13 shows a nip formed between a mold roll and a contoured pressureroll.

FIG. 14 is a transverse cross-section of a composite fastener tapeformed in the nip of FIG. 13.

DESCRIPTION OF EMBODIMENTS

Referring to FIG. 1, a lengthwise-continuous closure strip 100, such asfor sealing a bag, consists of a thin, sheet-form resin substrate 102with lengthwise-continuous, parallel bands 104 and 106 of loops andfastener elements, respectively, on its front face 108. Bands 104 and106 are equally spaced from the center “C” of the closure strip, suchthat when the strip is folded longitudinally at “C” to cover front face108, the fastener elements of band 1066 engage and retain the loops ofband 104 to form a releasable fastening. The fastener elements 110 ofband 106 are integrally molded with and extend from front face 108. Inthis embodiment, these fastener elements are in the form of J-hooks thatextend, in rows, along the length of the closure strip. Some of theJ-hooks face in opposite directions along the strip. Other fastenerelement shapes may also be employed, including those that overhang thesubstrate 102 in a widthwise direction. A suitable fastener elementshape is the CFM29 hook shape (of about 0.015 inch in height), availablein various products sold by Velcro USA in Manchester, N.H.

Band 104 of loops consists of a preformed, non-woven web of polymerfibers, which may include a stabilizing binder, and which are bonded tofront face 108 of substrate 102 at various points across the width andlength of the web. Suitable loop materials include those disclosed inU.S. patent application Ser. No. 08/922,292, the entire disclosure ofwhich is hereby incorporated by reference as if fully set forth.

In producing the batt from which the loop material described in theabove-referenced patent application is made, the material may bestretched during carding and pulled into a cloth-like mat consistingprimarily of parallel fibers. With nearly all of its fibers extending inthe carding direction, the mat has some strength when pulled in thecarding direction but almost no strength when pulled in the cardingcross direction, as cross direction strength results only from a fewentanglements between fibers. During crosslapping, the carded fiber matis laid in an overlapping zigzag pattern, creating a batt of multiplelayers of alternating diagonal fibers. The diagonal layers, which extendin the carding cross direction, extend more across the apron than theyextend along its length. For instance, we have used batt which has beencrosslapped to form layers extending at anywhere from about 6 to 18degrees from the cross direction of the finished product. The materialproperties and the manufacturing process can be affected by thecrosslapping angle. A steeper angle may balance the cross and machinedirection strengths, which may affect fastener performance and the easeof manufacturing. With more machine directional crosslapping, in somecases the initial machine direction stretch may be eliminated.

In another embodiment of forming the loop material (not illustrated),the second needling stage is omitted. Instead, needle looms of the firstneedling stage are configured to super-needle the batt in bothdirections. One loom needles the batt from the top at a rate of 254punches per square inch (39 per square cm), with the needles penetratingthe batt and extending through the bottom of the batt a distance of 10.2millimeters. Another loom then needles the batt from the bottom at arate of 254 punches per square inch (39 per square cm), with the needlespenetrating the batt and extending through the top of the batt adistance of 7.1 millimeters to form loops on the top side of the batt.The needling density, speed, and penetration of the looms may be variedto produce a product with substantially no backside loops, or withhook-engageable loops extending from both sides.

The binder used in the loop material may be at least partially in liquidform to wick into the entanglements before and while they aresubsequently tightened during stretching.

The non-woven web starting material used to manufacture the loopcomponent may be a fairly dense, needle punched, non-woven web of fiberslying in an apparently chaotic and tangled manner. This web is firststretched to 130 percent of its initial length in the machine direction.This stretching results in necking—the material narrows to 80 percent ofits initial width, from 45 inches (114 cm) to 36 inches (91 cm). It isthen coated with a binder. Next, it is stretched to 175% of its neckedwidth, from 36 inches (91 cm) to 63 inches (160 cm). An alternativeprocess employs heated rolls or “hot cans” or platens to stabilize theback side of the fabric in its stretched condition. This does notrequire a coating or adhesive when using thermoplastic fibers, as thefibers are locally fused together by heat. Cooled rolls engage the loopside of the fabric during passage, to prevent damage to thehook-engageable loops.

Preferably, the non-woven loop material in band 104 is very thin, suchas less than about 0.040 inch thick (more preferably, less than about0.020 inch thick), with web fibers held in a transversely stretchedcondition and free-standing loop structures extending from its exposedsurface. As discussed in the above-referenced patent applications, theloop structures extend from associated knots in the stretched web, whichmay be stabilized by liquid binder wicked into the knots and cured.Between knots, the thin fiber mat is not very dense and is sheer enoughto permit images to be readily seen through it. Overall, the loopmaterial has a basis weight (in its preformed state, including anypre-applied binder) of less than about 4 ounces per square yard (136grams per square meter), preferably less than about 2 ounces per squareyard (68 grams per square meter). Other details of this loop materialmay be found in the above-referenced applications. For applications inwhich the loop material is partially penetrated by resin of thesubstrate as the substrate is formed (as discussed below), the needledloop material is preferably only stretched in a transverse directiononly about 22 percent to leave a fair amount of loft and avoid totalpenetration.

In some instances, loop material 104 is partially encapsulated directlyin resin of the substrate as the substrate is formed in a continuousmolding process (described below). In other cases, it is bonded to theformed substrate, either by ultrasonic bonding, welding, or adhesives.

FIGS. 1A through 1D illustrate various patterns of variable bondingbetween loop material 104 and substrate 102. Such variable bondingpatterns correspond, in some cases, to variable resin penetration intothe web of the loop material, which may be achieved by employingdifferent arrangements of staking rings and/or barrier materials betweenthe loop material and substrate, both of which are discussed furtherbelow. In FIG. 1a, loop material 104 is only fully penetrated bysubstrate resin in narrow edge regions 114, and is less penetrated atits center. For instance, if loop material is about ¾ inch wide (W_(L)),then fully penetrated edge regions 114 may have a width of only about ⅛inch (w_(e)). The center region of the loop material is less penetratedand gently arches away from the substrate, presenting the loops forengagement. The inclined sides of the center arch can also help toenhance the peel strength of the fastening at the edges of the loopmaterial, as they resolve a small component of the peel force in atangential, or shear, direction.

In FIG. 1B, the loop material is fully bonded to the substrate in narrowbands 116 spaced inward from its edges, leaving edge regions 118relatively lightly bonded, or even loose. One advantage of this bondingpattern is that the inner edge region 118 on the inside of theassociated bag helps to deflect separation loads caused by shifting bagcontents, which would otherwise generate high peel forces between thefastener elements and the loops, into separation forces between the loopmaterial and substrate (as illustrated in FIG. 2A). The high bondingstrength of inner band 118 helps to avoid delamination of the loopmaterial from the substrate. Another advantage of this bonding patternis that it enhances initial peel strength of the fastening, as the outeredge region 118 of the loop material follows the fastener elementsduring peel until it is separated in shear (FIG. 2B).

The pattern of variable bonding shown in FIG. 1C creates transversepillows 120 of relatively lightly bonded, or loose, loop materialseparated by transverse bands 122 of relatively more fully bonded (e.g.,more deeply encapsulated) loop material. The loftiness of pillows 120 isexaggerated for illustration. This pattern provides some of thepeel-enhancing and load-shifting advantages of the pattern of FIG. 1B,due to the “free” pillow ends along the inner and outer edges of theloop material.

FIG. 1D illustrates a bonding pattern with longitudinal pillows 124 ofrelatively lightly bonded, or loose, loop material, separated bylongitudinal bands 126 of relatively more fully bonded (e.g., moredeeply encapsulated) loop material. Again, the loftiness of the pillowsis exaggerated for illustration. FIG. 1E is a variation of the patternof FIG. 1D, with each longitudinal band of more fully bonded materialseparated into longitudinally alternating regions of light and heavybonding. The regions of light and heavy bonding are staggered across theloop material, producing a checkerboard pattern of lofted loop pillows.In the pattern illustrated in FIG. 1F, the center region of loopmaterial 104 is heavily bonded to the substrate about the peripheries ofspaced apart, circular lofted regions 125 which are less firmly bonded.The exposed surfaces of the lofted loop pillows 125 extend outward topresent loops for engagement. Other shapes of lofted regions 125, suchas ovals, may also be employed. One of the edge regions of the loopmaterial of FIG. 1F is similar to the edge regions shown in FIG. 1B,while the other forms transverse pillows similar to those of FIG. 1C.FIG. 1G shows a bonding pattern with edge regions 128 of alternatinglight and heavy bonding, and a center region bonded in only isolatedregions 130. The bonding patterns described above may be mixed andvaried for different applications, as required.

Referring back to FIG. 1, molded into the front face 108 of substrate102 along its center is a hump-shaped longitudinal rib 132 between apair of grooves 134 molded into front face 108. As shown in FIG. 1H, oneexample of this rib 132 has a height of about {fraction (1/32)} inch anda width of about {fraction (1/32)} inch at its base. The rib may have ahump-shaped profile, as shown, or a rectangular cross-section withparallel sides. The rib is preferably longitudinally continuous, asshown, but may alternatively be formed as a row of appropriately shapedprotrusions. At least one of the flat regions 135 between grooves 134and the loop and hook bands 104 and 106 in FIG. 1 contains, in somecases, a layer of adhesive such as a pressure sensitive adhesive (notshown), for providing a reclosable seal for applications where aresealable opening is desired. In these instances surfaces 135 providean airtight, non-ventilated seal when the bag is closed, and supplementthe mechanical closure strength of the hook and loop fasteners.Preferably, an adhesive is employed which has been compounded so that itsticks primarily only to itself or to the opposing face of thesubstrate, so as to not pick up excessive debris from the bag contents.In other, non-illustrated embodiments, either grooves 134 or rib 132, orboth, are formed on the back face of the substrate, opposite thefastener elements and loop material.

The formed closure strip 100 is permanently installed at the openableend of a bag by attaching edge regions 136 of the closure strip to outeredges of the bag at its opening, with the loop and hook bands facingeach other, as shown in FIG. 3. The bag may be attached to the back faceof the closure strip as shown, in which case edge regions 136 aredefined on the back face of the closure strip, or on the front face,with the edges of the bag on the inside. Methods of attaching theclosure strip to the bag include, but are not limited to, welding,gluing, adhering or stitching. One preferable method of attaching aclosure strip to a bag of a compatible resin is by directly welding theresin of the closure substrate to the resin of the bag, as discussedbelow. In this manner, polyethylene closure strips may be readily weldedto polyethylene bags.

FIG. 4A illustrates a sealed bag 138 having a polyethylene body 140welded to closure strip 100 across its openable end. Preferably, thethickness of the substrate of the closure strip is about the same as thethickness of the material of the bag body, in the range of 0.002 to0.005 inch. Substrates of up to at least 0.015 inch in thickness,however, may be produced by the methods described below. To initiallybreak the seal and open the bag, the outer fold of closure strip 100 isgrasped and pulled, thereby tearing the folded edge from the bag fromone end of the bag to the other, as shown in FIG. 4B. In grasping theouter fold of the closure strip, the middle rib 132 is grasped betweenthe thumb and forefinger. Rib 132 thus provides an edge of increasedthickness for easy grasping. As the folded edge of the closure strip istorn away, the closure strip tears along grooves 134. Grooves 134function as frangible tear points for initially opening the associatedbag, and may be straddled by an associated local thickening of thesubstrate, such as in the form of rows of raised bumps (not shown) todirect the propagation of the tear along the grooves.

Preferably, the resin of the substrate of the closure strip iscompatible with the resin of the bag body, to enable direct welding ofthe two together. In situations where this is not practical, a separatelayer of a bag-compatible material may be provided on the closure strip.For example, a layer of paper 142 may be bonded to either the front faceof the closure strip (e.g., in edge regions 136 in FIG. 1), or acrossthe back face of the closure strip as shown in FIG. 6, or along just theedges of the back face of the closure strip (not shown). The paper 142may be directly bonded to the resin of the substrate (e.g., during theforming of the substrate, as described below), or joined with adhesiveafter the substrate is formed.

FIG. 7 illustrates one method and apparatus for producing theabove-described closure strips. The method builds upon the continuousextrusion/roll-forming method for molding fastener elements on anintegral, sheet-form base described by Fischer in U.S. Pat. No.4,794,028, and the nip lamination process described by Kennedy, et al.in U.S. Pat. 5,260,015, the details of both of which are incorporatedherein by reference. The relative position and size of the rolls andother components is not to scale. An extrusion head 150 supplies acontinuous sheet of molten resin to a nip 152 between a rotating moldroll 154 and a counter-rotating pressure roll 156. Mold roll 154contains an array of miniature, fastener element-shaped mold cavitiesextending inward from its periphery (not shown) for molding the fastenerelements. Pressure in nip 152 forces resin into the fastener elementcavities and forms the substrate. The formed product is cooled on themold roll until the solidified fastener elements (e.g., hooks) arestripped from their fixed cavities by a stripper roll 158. Along withthe molten resin, a continuous strip of loop material 160 (which becomesloop band 104 in FIG. 1) is fed into nip 152, where it is partiallyimpregnated by resin and becomes permanently bonded to the front face ofthe substrate. Thus the product 162 which is stripped from the mold rollincludes both fastener elements and loops.

For higher production rates, two or more widths of closure strip may besimultaneously produced on a single mold roll, and later split andspooled. Referring also to FIG. 8, two strips 160 of loop product arefed in parallel into positions 164 along nip 152. Molten resin isintroduced across the entire nip, forming two bands of hooks in regions166. Mold roll plates of appropriate widths and edge configurations arearranged to produce the ribs and grooves at the center of each closurestrip. A splitting channel ring 168 at the center of the mold rollproduces a splitting channel in the product, along which the resultingtape is split by a blade 170 (FIG. 7; either stationary or rotating)into two separate runs of closure strip which are separately spooled.

FIG. 7 also indicates several variations of the above-described method.For instance, rather than introduce the loop material 160 through nip152 and thereby join it to the substrate as the substrate is molded, theloop material may be joined to the substrate after the substrate hasbeen formed, such as is indicated by the run 160′ of loop material shownin dashed outline. In this case, front face idler 172 is heated and hasa contoured surface for producing the desired pattern of bonding betweenthe loop material and the substrate. Paper may be joined to the backface of the substrate, to produce the product shown in FIG. 6, by eitherrunning a strip 174 of paper through nip 152 on the pressure roll sideof the resin, or by adhering adhesive-coated paper 174′ to the formedsubstrate either at stripping roll 158 or at idler 176. In some cases,adhesive-coated paper 174′ includes a transfer coating, such that itspaper backing may be peeled from the adhesive on the back of the productto secure the back of the final product to a supporting surface. Theadhesive applied to the back of the product in this manner may be eithera pressure-sensitive or heat-activated adhesive, for instance. Fordecreasing the permeability of the final product, a second flow of resin(either molten or in the form of a film) may be added to the nip againstpressure roll 156, as strip 174 is shown, to form a backing on the finalproduct. For instance, a layer of polyester may be added to reduce thepermeability of a polyethylene closure strip, such as for packagingcertain foods. The pattern of penetration of resin into the loopmaterial in nip 152 is optionally controlled by adding a strip ofbarrier material 178 between the loop material and the molten resin.Barrier material 178 may be, for instance, a perforated paper or filmthat allows resin to pass into the loop material in selected regions butinhibits its flow into other regions, such as for producing the bondingpattern of the center region of loop material shown in FIG. 1G. Thebarrier material may also be a homogeneous sheet of material having ahigh porosity, equally limiting the penetration of resin into the loopmaterial across the width of the barrier material. Rather than beintroduced as a separate sheet, the barrier material may be pre-appliedto the surface of loop material 160 and may be in the form of a binderlocated in discrete areas of the loop material and locally encapsulatingfibers of the loop material, for instance. In many cases, the barriermaterial will be narrower than the loop material, and centered along thewidth of the loop material, to enable full penetration of resin into theedges of the loop material. In some cases, however, as to produce thebonding pattern of FIG. 1B, for instance, thin strips of barriermaterial may be run into the nip along the edges of the loop material toinhibit the bonding of edge regions 118 (FIG. 1B) to the substrate.Other arrangements of barrier and loop materials, and resulting bondingpatterns, will be apparent upon reading this disclosure. In all cases,the barrier material should be selected for its low material cost andweight, as it will most likely be permanently bonded to the substrateand become an integral part of the final product.

FIG. 9 illustrates the bonding of the loop material 160 to the resin ofthe substrate in area 164 of nip 152 (FIG. 8). “Staking” rings 180 oneither side of a reduced diameter plate 182 engage the edges of the loopmaterial to locally hold the edges of the loop material against theresin of the substrate as the resin forms the substrate under nippressure, thereby ensuring heavy penetration of the loop material inpredetermined areas along its edges. This configuration shown in FIG. 9produces the bonding pattern illustrated in FIG. 1A, the staking rings180 forming heavily bonded edge regions 114, the width we correspondingto the width of the staking ring. The staking rings may extend slightlybeyond the nominal mold roll diameter, as shown in FIG. 9, or be flushwith adjoining mold roll rings (as shown in FIG. 9A, for example).

To form a row of heavily bonded points separated by regions of lowerresin penetration, some staking rings 180 have a contoured outer edge asshown in FIG. 10. A series of protrusions 184 extending beyond thenominal diameter D_(s) of the staking ring cause the resin to locallypenetrate farther into the loop material. In this example configuration,D_(s) is 9.968 inches, the height (h_(s)) of each protrusion 184 is0.014 inch, and the inner and outer radii (R) at the flank of eachprotrusion is 0.015 inch. The protrusion pitch (P_(s)) is 0.190 inch,and the length of the flat between protrusions (w_(f)) is 0.130 inch.The dimensions of the protrusions are selected to attempt to optimizethe maximum approach angle α_(f) of the protrusion flank with respect toa local ring tangent. A steep approach angle (i.e., an abrupt change inring diameter) can cause a sharp local increase in nip pressure and anundesirable local flooding of the front side of the loop material withresin. Such flooded areas can create local “depth stops” to matingfastener elements, reducing the fastener element penetration into theloop material. A zero approach angle (i.e., no protrusions) would resultin a homogeneous resin penetration beneath the staking ring, which maynot be as desirable as local loop material “pillowing” (discussed above)in some applications. The maximum approach angle α_(f) in theillustrated staking ring embodiment is about 40 degrees. A shallowerangle (e.g., of about 30 degrees) may be preferable in some cases, asmay a longer spacing w_(f) between protrusions to provide longer, loftedpillow regions.

FIG. 9A shows a staking ring configuration for producing the bondingpattern shown in FIG. 1E. Staking rings 186 having the profile shown inFIG. 10 are stacked together with staggered protrusions, such that thepattern of heavily bonded regions resembles a checkerboard withelongated “pillows” extending outward between the heavily bondedregions. The width w_(s) of each ring is about 0.018 inch.

This in situ staking method for attaching loop material to the resin ofa fastener substrate as the substrate is being formed has broadapplicability to the production of composite touch fasteners. Forexample, FIG. 13 shows a nip 152′ between a mold roll 154′ and apressure roll 156′. Mold roll 154′ contains many thin fastener elementmolding rings 214, which may be alternated with spacer rings (notshown), to integrally mold fastener elements extending from one side ofa sheet-form base as taught by Fischer. In this case, however, pressureroll 156′ has a pattern of protrusions 216 extending from its otherwisesmooth surface. The protrusions locally narrow gap 152′ in discreteregions, causing a variation in nip pressure during formation of thefastener tape. Running a fibrous preformed material through the nipagainst the pressure roll with the molten resin, as taught by Kennedy,et al., will, in this configuration, cause fibers of the preformedmaterial to be encapsulated more fully in the resin in areascorresponding to protrusions 216. This in situ “staking” method isparticularly useful when the fibrous preformed material is a veryporous, thin material such as a needled non-woven web with a low basisweight. The pattern of protrusions on the pressure roll is selected toform an inverse pattern of lofted “pillows” of loop material at mostonly partially encapsulated in the substrate resin.

FIG. 14 is a transverse cross-section of a composite fastener tape 218produced in this fashion, having an array of hook-shaped fastenerelements 220 extending from one side of the substrate 222, and alightweight, non-woven web of loop material 224 permanently bonded to anopposite side of the substrate. Loop material 224 is coextensive withthe substrate in this case (i.e., it extends across the full width ofthe substrate), but is fully encapsulated in substrate resin only indiscrete regions 226. Between regions 226, the loop material forms theabove-described “pillows” 228, or lofted regions, which are not fullyencapsulated in resin. The loft of pillows 228 enables the heads offastener elements 220 to penetrate the loop material and engageindividual fibers during fastening. A similarly contoured pressure roll156′ (FIG. 13) may also be employed to attach a strip of loop materialto the fastener element side of a fastener tape.

FIG. 11 illustrates an alternative method and apparatus for forming theabove-described closure strips. The contoured surface of an extrusionhead 188 (sometimes called an injection head) is placed adjacent a moldroll 154 (with fixed fastener element molding cavities as describedabove with respect to FIG. 7), and a continuous flow of molten resin isinjected under pressure into the gap 190 defined between head 188 andmold roll 154, filling the fastener element cavities and forming thefront and back faces of the substrate. The configuration andconstruction of mold roll 154 is the same as is shown in FIG. 8, inwhich member 156 may be taken to be the adjoining extrusion head. Thestrip 160 of loop material is fed through a predetermined region of gap190, and held up against the surface of mold roll 154 by resin pressurein the gap. In this manner, the loop material is partially impregnatedwith substrate resin and permanently bonded to the front face of thesubstrate. In applications where it is not possible to fill the fastenerelement cavities without completely saturating the loop surface of theloop material with resin, a strip of barrier material 178 may be fedthrough gap 190 between head 188 and loop material 160. Barrier material178 is discussed in more detail above with respect to FIG. 7. A strip174 of paper or other suitable backing material may be laminated to theback face of the substrate while the molded product is retained on roll,by pressure supplied by a pressure roll 192, as shown in dashed outline.Alternatively, a strip of adhesive-coated paper 174′ may be adhered tothe formed substrate either at stripping roll 158 or at idler 176.

FIG. 12 illustrates a method and apparatus for forming and filling bags(such as bag 138 of FIG. 4A). Closure strip 100 and a sheet of bagmaterial 194 are each folded and fed about a longitudinal mandrel 196,with their edges overlapping at two points. In the embodiment shown,both the bag material 194 and the substrate of closure strip 100 arepolyethylene. Two heated rollers 198 (only one visible from theperspective illustrated) weld the edges of the closure strip and bagmaterial together to form a continuous tube 200 with two longitudinalsealed seams. In the apparatus shown, tube 200 extends upward through alower sealing/cutting device 202 and an upper sealing device 204. In thebag forming and filling sequence, tube 200 is advanced upward until itsopen end is aligned with upper sealing device 204. Lower sealing/cuttingdevice 202 then forms a transverse seal across the tube to form onesealed side of the resulting bag. The bag is then filled from above,through the still open end of the tube, with material supplied throughchute 206. After a predetermined amount of material has been releasedinto the bag, the open end of the tube is sealed by upper sealing device204 to form a sealed bag 138, which is then severed from tube 200 bycutting the tube just below the previously formed transverse seal bylower sealing/cutting device 202. The resulting bag 138 has one edge 208of folded bag material 194, two sealed edges 210, and one edge 212 offolded closure strip 100. Other standard sequences of forming andfilling bags from tubes of preform material are known to those of normalskill in the art of bag-making. For instance, for sealing thepaper-covered surface of closure strip 100′ (FIG. 6) to a paper bagmaterial 194, a layer of adhesive would normally be applied between theoverlapping paper edges of the closure strip and bag material.

Similarly, the closure strip described above may be provided inform-filled packaging, such as that currently employed to packagecookies and candy bars, as a releasable closure. In such cases, theclosure strip may be located at one sealed end of the package, oppositeanother sealed end, or along a longitudinal seam of the package. By“bag”, we mean to include such packages.

Other embodiments will be understood to fall within the scope of thefollowing claims.

What is claimed is:
 1. An elongated closure strip comprising: asheet-form resin substrate having a front face from which an array ofloop-engageable fastener elements extend in a discrete, longitudinalband, integrally molded with resin of the substrate; and a loop stripcarried on the front face of the substrate and comprising a non-wovenweb of fibers forming a discrete band of hook-engageable loops extendingalong the length of the closure strip, the band of fastener elementsextending longitudinally along the length of the closure strip andspaced apart from the band of loops, with the substrate defining a pairof grooves extending longitudinally along the length of the closurestrip between the band of loops and the band of fastener elements. 2.The closure strip of claim 1 wherein the web has a basis weight of lessthan about 4 ounces per square yard.
 3. The closure strip of claim 2wherein said basis weight is less than about 2 ounces per square yard.4. The closure strip of claim 1 wherein the non-woven web comprises aneedled web in a stretched condition.
 5. The closure strip of claim 1wherein the loop strip has width defined between two longitudinal edgesthereof, at least some of the fibers of the loop strip being affixed tothe substrate across said width.
 6. The closure strip of claim 5 whereinat least some of the fibers of the loop strip are encapsulated by resinof the substrate across said width.
 7. The closure strip of claim 6wherein the loop strip has a fiber density which is substantiallyconstant across its width, and wherein the loop strip comprises discreteregions which are substantially more encapsulated by resin than otherregions thereof.
 8. The closure strip of claim 7 wherein said discreteregions are spaced apart longitudinally along the loop strip.
 9. Theclosure strip of claim 7 wherein said discrete regions extend lengthwisealong the loop strip and are spaced apart widthwise.
 10. The closurestrip of claim 7 wherein said discrete regions are arranged in acheckerboard pattern.
 11. The closure strip of claim 1 wherein the loopstrip has two longitudinal edge regions and a center region between theedge regions, the edge regions being affixed to the substrate and thecenter region being substantially loose from the substrate.
 12. Theclosure strip of claim 11 wherein the center region of the loop stripdefines a gentle arc extending away from the substrate.
 13. The closurestrip of claim 1 further comprising, between the substrate and the loopstrip, a barrier layer of a different material than the substrate. 14.The closure strip of claim 13 wherein the barrier layer comprises paper.15. The closure strip of claim 13 wherein the barrier layer comprisespolymer resin.
 16. The closure strip of claim 1 wherein open-endedpockets are defined between an edge of the loop strip and the substrate.17. The closure strip of claim 1 wherein the loop strip comprises twolongitudinal edge regions and a center region between the edge regions,the edge regions having fibers directly encapsulated within resin of thesubstrate, the closure strip further comprising a binder connectingfibers of the center region of the loop strip to resin of the substrate,the binder being of a different material than the substrate.
 18. Theclosure strip of claim 1 wherein the loop material has two longitudinaledges, one of the longitudinal edges having discrete regions loose fromthe substrate.
 19. The closure strip of claim 1 wherein the grooves aredefined by molded surfaces of the substrate.
 20. The closure strip ofclaim 1 wherein the grooves are defined in the front face of thesubstrate.
 21. The closure strip of claim 1 wherein the grooves arelengthwise continuous.
 22. The closure strip of claim 1 wherein the loopmaterial has a longitudinal edge region loose from the substrate. 23.The closure strip of claim 1 wherein the loop material has twolongitudinal edge regions running along either side of a center region,the edge regions being loose from the substrate.
 24. The closure stripof claim 1 wherein the front face of the substrate has two longitudinaledge regions void of fastener elements and loops.
 25. The closure stripof claim 24 wherein the longitudinal edge regions of the front face ofthe substrate are covered with a layer of adhesive for permanentlyattaching the closure strip to opposite sides of a bag.
 26. The closurestrip of claim 24 wherein the longitudinal edge regions of the frontface of the substrate comprise exposed resin of the substrate, forpermanently welding the closure strip to opposite sides of a bag formedof a compatible material.
 27. The closure strip of claim 1 wherein thesubstrate has a back face opposite the front face, the back faceincluding longitudinal edge regions, the closure strip furthercomprising a layer of adhesive disposed on the longitudinal edge regionsof the back face for permanently attaching the closure strip to oppositesides of a bag.
 28. The closure strip of claim 1 wherein the substratehas a back face opposite the front face, the back face includinglongitudinal edge regions comprising exposed resin of the substrate, forpermanently welding the closure strip to opposite sides of a bag formedof a compatible material.
 29. The closure strip of claim 1 wherein thesubstrate is formed of polyethylene.
 30. The closure strip of claim 1further comprising an adhesive strip carried on the front face of thesubstrate between the band of fastener elements and the band of loops,the adhesive strip having an exposed surface arranged to contact thefront face of the closure strip when the closure strip is folded toengage the loops with the fastener elements, to retain the closure stripin a folded state.
 31. The closure strip of claim 1 further comprising:a first adhesive strip carried on the front face of the substratebetween the band of fastener elements and the pair of grooves; and asecond adhesive strip carried on the front face of the substrate betweenthe band of loops and the pair of grooves; the first and second adhesivestrips having exposed surfaces arranged to contact each other when theclosure strip is folded to engage the loops with the fastener elements,to retain the closure strip in a folded state.
 32. The closure strip ofclaim 1 further comprising a layer of paper permanently adhered to thesubstrate.
 33. The closure strip of claim 32 wherein the layer of paperis carried on the front face of the substrate, in longitudinal edgeregions thereof.
 34. The closure strip of claim 32 wherein the substratehas a back face opposite the front face, the paper being carried on theback face.
 35. The closure strip of claim 32 wherein the layer of paperis disposed between a center region of the loop strip and the substrate.36. An elongated closure strip comprising: a sheet-form resin substratehaving a front face and a back face; a loop strip carried on the frontface of the substrate and forming a discrete band of hook-engageable,extended loops along the length of the closure strip; an array ofloop-engageable fastener elements carried on the front face of thesubstrate and forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaced apartfrom the band of loops; the substrate defining a pair of groovesextending longitudinally along the length of the closure strip betweenthe band of loops and the band of fastener elements; and a longitudinalrib integrally molded with and extending from the substrate between thepair of grooves.
 37. The closure strip of claim 36 wherein the loopstrip comprises a non-woven web of entangled fibers forming the loopsand having a basis weight of less than about 4 ounces per square yard.38. The closure strip of claim 36 wherein the grooves and rib aredisposed on the front face of the substrate.
 39. An elongated closurestrip comprising: a sheet-form resin substrate having a front face and aback face; a loop strip carried on the front face of the substrate andforming a discrete band of hook-engageable, extended loops along thelength of the closure strip, the loop strip having width and a fiberdensity which is substantially constant across its width, the loop stripbeing at least partially encapsulated in resin of the substrate acrossits width, the loop strip having discrete regions which are moreencapsulated by resin than other regions thereof; and an array ofloop-engageable fastener elements carried on the front face of thesubstrate and forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaced apartfrom the band of loops.
 40. The closure strip of claim 39 wherein thefastener elements are integrally molded with resin of the substrate. 41.The closure strip of claim 39 wherein the substrate has a back faceopposite the front face, the back face including longitudinal edgeregions, the closure strip further comprising a layer of adhesivedisposed on the longitudinal edge regions of the back face forpermanently attaching the closure strip to opposite sides of a bag. 42.The closure strip of claim 39 wherein the substrate has a back faceopposite the front face, the back face including longitudinal edgeregions comprising exposed resin of the substrate, for permanentlywelding the closure strip to opposite sides of a bag formed of acompatible material.
 43. The closure strip of claim 39 furthercomprising an adhesive strip carried on the front face of the substratebetween the band of fastener elements and the band of loops, theadhesive strip having an exposed surface arranged to contact the frontface of the closure strip when the closure strip is folded to engage theloops with the fastener elements, to retain the closure strip in afolded state.
 44. The closure strip of claim 39 wherein the substratedefines a pair of grooves extending longitudinally along the length ofthe closure strip between the band of loops and the band of fastenerelements.
 45. The closure strip of claim 39 further comprising alongitudinal rib integrally molded with and extending from the frontface of the substrate between the band of loops and the band of fastenerelements.
 46. A composite touch fastener comprising an elongated,sheet-form resin substrate; a fibrous loop strip partially encapsulatedin resin of the substrate, the loop strip having discrete regions whichare substantially more encapsulated by resin than other regions thereof;and an array of loop-engageable fastener elements integrally molded withresin of the substrate.
 47. The composite touch fastener of claim 46wherein the loop strip has width defined between two longitudinal edgesthereof, and a substantially constant fiber density across said width.48. The composite touch fastener of claim 46 wherein the strip of loopmaterial has regions of substantially higher loft than regionscorresponding to said discrete regions which are substantially moreencapsulated by resin.
 49. The composite touch fastener of claim 46wherein the strip of loop material comprises a non-woven web ofentangled fibers forming loops and having a basis weight of less thanabout 4 ounces per square yard.
 50. The composite touch fastener ofclaim 46 wherein the strip of loop material comprises a non-woven web offibers.
 51. An elongated closure strip comprising: a sheet-form resinsubstrate having a front face; a loop strip carried on the front face ofthe substrate and comprising a non-woven web of fibers having a basisweight of less than about 4 ounces per square yard and a substantiallyconstant fiber density throughout, the loop strip forming a discreteband of hook-engageable loops extending along the length of the closurestrip, at least some of the fibers of the loop strip being at leastpartially encapsulated by resin of the substrate; and an array ofloop-engageable fastener elements integrally molded with resin of thefront face of the substrate and forming a discrete band of fastenerelements extending longitudinally along the length of the closure stripand spaced apart from the band of loops; the front face of the substratedefining a pair of grooves defined by molded surfaces extendinglongitudinally along the length of the closure strip between the band ofloops and the band of fastener elements, a longitudinal rib integrallymolded with and extending from the front face of the substrate betweenthe band of loops and the band of fastener elements, and twolongitudinal edge regions void of fastener elements and loops.
 52. Anelongated closure strip comprising: a sheet-form resin substrate havinga front face; a loop strip carried on the front face of the substrateand comprising a non-woven web of fibers forming a discrete band ofhook-engageable loops extending along the length of the closure strip,the loop strip having width defined between two longitudinal edgesthereof, at least some of the fibers of the loop strip being affixed tothe substrate across said width by being encapsulated by resin of thesubstrate across said width, the loop strip having a fiber density whichis substantially constant across its width, and wherein the loop stripcomprises discrete regions which are substantially more encapsulated byresin than other regions thereof; and an array of loop-engageablefastener elements integrally molded with resin of the front face of thesubstrate and forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaced apartfrom the band of loops.
 53. The closure strip of claim 52 wherein saiddiscrete regions are spaced apart longitudinally along the loop strip.54. The closure strip of claim 52 wherein said discrete regions extendlengthwise along the loop strip and are spaced apart widthwise.
 55. Theclosure strip of claim 52 wherein said discrete regions are arranged ina checkerboard pattern.
 56. An elongated closure strip comprising: asheet-form resin substrate having a front face; a loop strip carried onthe front face of the substrate and comprising a non-woven web of fibersforming a discrete band of hook-engageable loops extending along thelength of the closure strip; an array of loop-engageable fastenerelements integrally molded with resin of the front face of the substrateand forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaces apartfrom the band of loops; and a barrier layer of a different material thanthe substrate between the substrate and the loop strip.
 57. The closurestrip of claim 56 wherein the barrier layer comprises paper.
 58. Theclosure strip of claim 56 wherein the barrier layer comprises polymerresin.
 59. An elongated closure strip comprising: a sheet-form resinsubstrate having a front face; a loop strip carried on the front face ofthe substrate and comprising a non-woven web of fibers forming adiscrete band of hook-engageable loops extending along the length of theclosure strip, the loop strip comprising two longitudinal edge regionsand a center region between the edge regions, the edge regions havingfibers directly encapsulated within resin of the substrate, the closurestrip further comprising a binder connecting fibers of the center regionof the loop strip to resin of the substrate, the binder being of adifferent material than the substrate; and an array of loop-engageablefastener elements integrally molded with resin of the front face of thesubstrate and forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaced apartfrom the band of loops.
 60. An elongated closure strip comprising: asheet-form resin substrate having a front face; a loop strip carried onthe front face of the substrate and comprising a non-woven web of fibersforming a discrete band of hook-engageable loops extending along thelength of the closure strip; an array of loop-engageable fastenerelements integrally molded with resin of the front face of the substrateand forming a discrete band of fastener elements extendinglongitudinally along the length of the closure strip and spaced apartfrom the band of loops; and a longitudinal rib integrally molded withand extending from the front face of the substrate between the band ofloops and the band of fastener elements.
 61. The closure strip of claim60 wherein the substrate has a back face opposite the front face, theback face including longitudinal edge regions, the closure strip furthercomprising a layer of adhesive disposed on the longitudinal edge regionsof the back face for permanently attaching the closure strip to oppositesides of a bag.
 62. The closure strip of claims wherein the substratehas a back face opposite the front face, the back face includinglongitudinal edge regions comprising exposed resin of the substrate, forpermanently welding the closure strip to opposite sides of a bag formedof a compatible material.
 63. The closure strip of claim 1 furthercomprising an adhesive strip carried on the front face of the substratebetween the band of fastener elements and the band of loops, theadhesive strip having an exposed surface arranged to contact the frontface of the closure strip when the closure strip is folded to engage theloops with the fastener elements, to retain the closure strip in afolded state.
 64. An elongated closure strip comprising: a sheet-formresin substrate having a front face; a loop strip carried on the frontface of the substrate and comprising a non-woven web of fibers forming adiscrete band of hook-engageable loops extending along the length of theclosure strip; an array of loop-engageable fastener elements integrallymolded with resin of the front face of the substrate and forming adiscrete band of fastener elements extending longitudinally along thelength of the closure strip and spaced apart from the band of loops; andan adhesive strip carried on the front face of the substrate between theband of fastener elements and the band of loops, the adhesive striphaving an exposed surface arranged to contact the front face of theclosure strip when the closure strip is folded to engage the loops withthe fastener elements, to retain the closure strip in a folded state.